Btw, just an information. If she stays longer than 6 months even after extending her stay with permission from USCIS, I noticed when he/she tries to renew his/her visitor visa, chances are high that it will be denied. Couple of my friend's parents had that situation. One was denied in second and another was denied in their third extension. Also getting a drivers license in visitor visa seems red flag when going in for renewal of visitor visa.